The move by Whitman to back the Democratic junior Senator came about because “in the spring of 2003, some technology leaders were interested in announcing their support for Boxer, so our campaign went out and talked to a wide range of leaders. And Meg Whitman was among them,” Kapolcyznski said.

“She agreed to endorse the Senator…there was a fundraising event in Silicon Valley later in the year and Whitman maxed out to the campaign,” she said.

Why would Whitman, who has repeatedly said that she backs Republican values, throw her support to Boxer — reviled by Republicans as one of the U.S. Senate’s most liberal members?

“(Boxer) has been a strong supporter of research and development funding, which benefits Silicon Valley,” Kapolcyznski said. “She’s worked to promote exports of technology overseas and she’s always had a strong relationship with the technology industry.”

Whitman spokesman Sarah Pompei, asked about the endorsement, said today that “at the same time that Barbara Boxer was fighting against internet taxes, which earned Meg Whitman’s support, Steve Poizner was arguing for tax increases to support transportation projects and cover budget shortfalls in Sacramento. It’s nothing new, Meg Whitman has supported members of both parties who fought against internet taxes.”

Indeed, Cisco System chair and CEO John Chambers, today a member of Whitman’s economic task force and one of her major backers, actually headed the Boxer Tech group. He gushed that he was in full support of her re-election because her “leadership on Silicon Valley issues such as stock options, broadband, R&D tax credit, and export controls shows she is responsible to the needs of the California economy.”

Whitman, the eBay CEO, was so convinced of Boxer’s strength that she, too, released her own statement. “Barbara Boxer is a courageous leader and friend of California’s technology industry,” Whitman said in the 2003 Democratic campaign release.

It’s a quote Boxer may end up using in her 2010 re-election campaign against either California Assemblyman Chuck DeVore or former Hewlett-Packard CEO Carly Fiorina, two Republicans who are aiming for her seat.

The news that Whitman backed and endorsed Boxer — considered Public Enemy Number One for the GOP in California — comes just days after the eBay CEO faced heat over her failure to vote for decades. She assured grassroots activists at the state GOP convention last week of her solid Republican credentials.

“I’m a Republican, and you’ll find I’m a darn good one,” she told them. “I’ve committed myself to running for one of the toughest chief executive jobs on the planet because I believe Republican ideals, truly and consistently applied, will save this state.”